Expansion router-bit



(No Model.)

P. W. BRITTON. EXPANSION ROUTER BIT.

No. 596,420. Patented Dec, 28, 1897.

a A N ITED STATES PATENT FFICEQ FRANKLIN W. BRITTON, OF BRA INERD, MINNESOTA.

EXPANSION ROUTER-BIT.

SPECIFICATION forming part of Letters Patent No. 596,420, dated December 28, 1897.

Application filed April 19, 1897. Serial No. 632,837. (No model.)

To all whom it may concern:

Be it known that I, FRANKLIN W. BRITTON, a citizen of the United States, residing at Brainerd, in the county of Crow YVing and State of Minnesota, have invented certain new and useful Improvements in Expansion Router-Bits, of which the following is a specification.

My invention relates to improvements in expansion router-bits, and has for one of its objects to provide a tool with which circles or circular grooves of different diameters may be cut.

Another object of my invention is to provide a tool with which circular dados of various diameters may be out.

Another object of my invention is to provide a tool which will cut circular dados of various diameters and having their surfaces intermediate of the center and circumference cut in different forms.

Another object of my invention is toprovide a tool with which wheels of different diameters may be out.

These objects I accomplish in the manner and by the means hereinafter more fully described in detail,and particularly pointed out in the claims, reference being had to the accompanying drawings in which the same figures indicate like parts in all the views.

Figure 1 is a front elevation of myim proved expansion router-bit. Fig. 2 is a top plan view of same. Fig. 3 is an end view of the expansion-arm of same. Fig. 4: is a detail view of the guide of same. Fig. 5 is adetail view of the cutting-knife of same. Fig. 6 is a detail view, on line so a: of Fig. 2, of the slot in the cross-piece.

The shank 1, forming the body of the tool, has its upper end 2 squared and tapered to adapt it to a brace or bit stock or handle and its lower end 3 and bottom squared, with a screw-threaded hole in the bottom adapted to receive and secure the bit 4 and with a mortise 5 horizontally and laterally through its lower end 3, into which mortise is inserted an arm 6, having its upper surface graduated in inches and fractions of an inch and being clamped in said mortise 5 by a thumb-screw 7, which enters said mortise 5 at right angles through the side of the lower end 3 of the shank 1.

The free end of the arm 6 is inserted into the mortise 8 in the cross-piece 9, where it is clamped bya screw 10. The forward end of said cross-piece 9 has a mortise 11, in which is inserted a guide 12, being clamped therein by a thumb-screw 13, and the rear end of said cross-piece 9 has a dovetailed vertical groove 14:, in which the router-bit 15 is secured by the clamp 16 and adjusted by a screw 17. In the bottom of the cross-piece 9 and just in front of the groove 14 for the router-bit 15 is an upwardly-inclined slot 18, into which one end of the knife 19 is inserted and secured by a screw 20.

The guide 12 has a shoe 21 turned in the direction the tool turns, having inserted in the heel of said shoe 21 and secured there by a a screw a piece of steel having cutting-lips 22 22 flush with the sides of the said shoe 21 and projecting below said shoe for the purpose of cutting into the surface of the material being worked and preventing the routerbit tearing it. Between said cutting-lips 22 the said steel is even with the bottom of said shoe 21. This allows the wear on the cuttinglips 22 to be made good without disturbing the guide 12. The upper end of the shank of the guide 12 is reduced in size to fit the mortise 11 in the cross-piece 9, forming the shoulder 23, between which and the bottom of the crosspiece 9 collars or washers 2 1 are inserted when it is desired to lengthen said guide 12.

The router-bit 15 has a straight cutting edge 25, behind and above which the shank is rounded off upward and above which in front the shank is formed so as to present to the ascending chips a surface inclining upward and outward.

The center bit 4 may be made in any way so as to take, hold of and enter the material upon which the tool is being used and has its upper end fitted to the screw-threaded hole in the bottom of the shank 1 and screw-thread ed complementary thereto.

A knife 19, having a cutting edge of any de sired form, may be used with my improved router-bit by inserting one end of said knife 19 in the slot 18 in the bottom of the crosspiece 9, where it is secured with a screw, and by inserting the upper end of the center-bit 4 through a hole provided for said center-bit 4 in the other end of said knife 19, the part Ioo containing said hole being bent so as to give the knife the proper inclination.

Having thus described my invention, what I claim as new, and desire to secure by Letters 2. In an expansion-bit provided witha shank, an extension-arm, a cross-piece on the end of said arm and a cutting-tool mounted 011 said cross-piece, a guide having a cuttingtool adjustably inserted in it, said cuttingtool having cutting-lips projecting at each side below the end of said guide and its surface between said cutting-lips level with the lower end of said guide, substantially as shown and described.

3. An expansion router-bit consisting of a shank having a removable center-bit, an adjustable graduated transverse arm mounted on said shank, a cross-piece on the end of said adjustable arm having a mortise in its forward end and a vertical dovetailedgroove on its rear end, a guide mounted in said mortise, said guide having a cutting-tool adjustably inserted in it, said cutting-tool having cutting-lips projecting from each side below the end of said guide and the surface between said cutting-lips level with the lower end of said guide and a cutting-tool mounted in said the cross-piece on the end of the expansionarm and at the other end passed over the head of the center-bit before said center-bit is screwed into the shank, substantially as shown and described.

5. An expansion router-bit consisting of a shank having a removable center-bit, an adj ustable graduated transverse arm mounted on said shank, a cross-piece on the end of said adjustable arm having a mortise in its forward end and a vertical dovetailed groove in its rear end, a guide mounted in said mortise having cutting-lips projecting from each side of its lower end and a cutting-tool mounted in said vertical dovetailed groove having a straight cutting edge and its forward surface above said cutting edge inclined outward and backward to allow the chips to pass off, substantially as shown and described.

6. An expansion router-bit consisting of a shank having a removable center-bit, an adjustable graduated transverse arm mounted on said shank, a cross-piece on the end of said adjustable arm having a mortise in its forward end and a vertical dovetailed groove in its rear end, a guide mounted in said mortise having cutting-lips projecting from each side of its lower end and a cutting-tool mounted in said vertical dovetailed groove having a straight cutting edge and its forward surface above said cutting edge inclined outward and backward to allow the chips to pass off, and a knife having one end inserted in an upward-inclined slot in said cross-piece and the other end passed over the upper end of said center-bit before it is inserted in said shank, substantially as shown and described.

In testimony whereof I hereto affix my signature in the presence of two witnesses.

FRANKLIN WV. BRITTON.

Witnesses:

I. U. 'WHITE, S. J. GREER. 

